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Mushroom Starch Test Kit

Does your mushroom supplement contain starch?

Thank you for purchasing our mushroom starch test kit and taking the first steps to determining whether the product you have is pure mushroom or not. The kit you have is designed to test for the presence of starch using iodine. It is called a colorimetric test and is very similar to titration tests done in high school chemistry.

Medicinal mushrooms generally have <5% starch. If a product claims to be pure mushroom then it should also conform to this rule.


Many retail mushroom supplement products are in fact not made from mushrooms. U.S. grown mycelium on grain is commonly sold as "mushroom" when it contains no mushrooms at all. On top of that, the grain on which the mycelium is grown on ends up in the final product, leading to a high amount of starch which also lowers the amount of fungal material present (what you want). Recent independent testinghas shown some "mushroom" products to be over 70% starch and 0% beta-glucans (not good).


Another example of added starch are carriers and flow agents like dextrose and maltodextrin. These cheap additives are often added in to help powders "flow" better during the manufacturing process. Typically very little is required but it can easily be overused. Some testing has shown up to 30% starch from flow agents.


This is why starch testing is such an important, yet simple, test which can show you if what you have is pure mushroom or not. Because the last thing you want is your money going towards starch when you wanted mushrooms.


  1. Get a mushroom product to test
  2. Add one gram of mushroom powder to 3 tablespoons of warm water. You will need to consult the Supplements Panel to see how much one gram is.
  3. Stir the mushroom powder into the warm water to dissolve it as much as possible.
  4. Using the pipette, add 10 drops of iodine to the water mixture and then stir it in.


Does the mushroom powder solution change color to a dark purple / black?

This confirms the presence of some type of starch. The starch material is diluting the amount of actual fungal material in the product and hence lowering the amount of active medicinal compounds (what you want) in the product.

In the case of a product grown in the US, you probably have a myceliated grain product, not a mushroom product.
The Science Behind the Test

Post Your Results

Post a short video of a starch test with your mushroom product on Facebook, Instagram, Twitter or YouTube with the hashtag #MushroomStarchTest and contact us with a link to your post. If your product shows the presence of starch, we will verify the link and send you a coupon code for $10 off your next Real Mushrooms purchase.